input value of regrocedure type should be complete function signature.
postgres=# select 'uni'::regprocedure; ERROR: expected a left parenthesis LINE 1: select 'uni'::regprocedure; ^
I think so it is not necessary, when function name is unique.
plpgsql_check uses regprocedure type parameters often and less strict input can be more user friendly - almost all business logic functions has uniq name. I don't propose to change a output. It will be same - complete function signature.